The present invention relates to cartridges providing protective housings for recording discs and, more particularly, to housings serving as protective devices for discs, such as optical discs, having recordings on one or both surfaces of the discs. These cartridges are used to protect the recorded surfaces of the discs and include a mobile shutter or door covering an access aperture and operable to uncover the aperture to allow optical reading and/or recording devices to access the disc surface for purposes of reading or making recordings on the surface.
The cartridges available on the market have a parallelepipedic shape, such as disclosed in the European applications EP-A-0260876, EP-A-0768662 and EP-A-0794532 and generally comprise ribs, which increase their thickness, to improve their stiffness because presently the discs are thin (xc2x11.3 mm.) but of a rather large size (8 to 12 cm. in diameter). Further, their shutters are mounted for translation on the outside of said cartridges with the main drawback that the user can easily manipulate them, thus gain access to the disc and damage its surfaces. These cartridges also comprise a discontinuity to induce the user to load them with the correct orientation in reading/recording units, but those discontinuities are not always effective and quite often the reading/recording units must incorporate specific means to check the proper orientation of a cartridge presented by a user before allowing any further insertion movement.
Furthermore, the almost universal use of a parallelepipedic cartridge to protect discs is the source of a large waste of space, almost 25% of the volume, which is in contrast with the present trend of the industry to manufacture very compact units.
In another field, the motion picture field, a cartridge has been proposed having a partially circular shape, as described in U.S. Pat. No. 3,554,462, but since it was designed for the storage of a reel of film, it is mainly the reel which protects the film and the opening allowing access to the film is set laterally in a parallelepipedic boss.
One object of the present invention is to overcome those various drawbacks by providing a cartridge for a recording disc which is simple, compact and stiff and provides a high level of protection.
Another object of the invention is to provide a cartridge having a shape which induces the user to insert it with the correct orientation in the appropriate reading and/or recording unit.
Additional characteristics and unique features will be evident from the following description of preferred embodiments of the invention to which improvements and modifications can be brought without departing from the scope of the invention as defined in the appended claims: